Safety device for elevators



Aug 30, 193 2. H. D. JAME$ 1,874,044

SAFETY DEVICE FOR ELEVATORS Filed May 27. 1929 2 Sheets-Sheet 1 Fig].

' INVENTOR Henry D. James.

ATTORN EY Aug. 30, 1932. H. D. JAMES SAFETY DEVICE FOR ELEVATORS Filed May'27, 1929 2 Sheets-Sheet 2 INVENTOR Henry D. James.

ATTORNEY loaded.

, partly in section and partly broken away,

Patented Aug. 30, 1932 retreat HENRY n. JAMES, or EDGEWOOD, PEN SYLVANIA, AssienozaTowEsrINeHoUsNnLEo- 'rnroa MANUFACTURING COMPANY, A ,ooaroaArio or PENNSYLVANIA 'sAPN'rY DE ICE FOR ELEvA'roRs Application filed May 27,

My invention relates generally to safetydevices for elevators and more particularly to the means for operating such safety devices.

5 The object of the invention, generally stated, is the provision of a safety device that shall be simple and efficient in operation and adapted for economical manufacture and installation.

A more specific object of my invention is to provide for placing the safety device in use every time the car is stopped and thereby insure its proper maintenance and action when needed to stop the car.

Another object of my invention is to provide for applying a braking effect to an elevator car each time a stop is made and for holding the car at a landing during the existence of astop thereat.

It is also an object of my invention to provide for'holding an elevator car rigidly level with a landing at which a stop is made, regardless of any variations in its load that may occur while it is being loaded and un- Further objects of my invention will, in part, be obvious and will, in part, appear iereinafter.

For an illustration of one of the many 90 forms my invention may take, reference may be had to the accompanying drawings in which: w

Figure 1 is a diagrammatic representation of an elevator and its control system provided with a safety device constructed in accordance with my invention;

Fig. 2 is an enlarged plan view, partly in section, of the safety device illustrated as applied to the car in Fig. 1;

Fig. 3 is a view, partly in front elevation,

of the safety device shown in Fig. 2'; V

Fig. 1 is a view, in detail, of the braking jaws that are attached to the safetydevice; and

Fig. 5 is a detail view of one of the auxiliarylevers for operating'the braking jaws of the safety device shown in Fig. 3.

The drawings illustrate a car G as suitably suspended by, a hoisting cable Ca that passes 1929. Serial No. 3 6,284.

over a hoisting drum D to a suitable counterweight Cw. The hoisting drum D is directly coupled to the armature EM of a hoisting motor EM.

A variable-voltage system of control may be provided for operating the elevator motor EM wherein the armature EM of the elevator motor is'connected in loop circuit with the armature G of a generator G. The generator G is provided with a separately excited field winding GF and a cumulative series field winding GSF. 1

The armature G of the generator G is suitably driven by means of a driving motor M, illustrated as being of the shunt-Wound type having its armature M and its field winding MF connected in shunt relation to a source of power designated as the supply conductors L1 and L2. The elevator motor EM has its field winding EMF connected, for constant- 7 supplied to the field winding. may be controlled by means of an intermediate-speed relay LR and a; high-speed relay HR.

The operation of the up-direction and the down-direction switches 1 and 2 may be controlled by means of the car switch Cs that is mounted upon the elevator car C in position to be actuated by an attendant on the car.

In order that the car C may be suitably positioned in its hatchway, it is provided with a plurality of guide shoes 10, 11, 12 and 13 that are adapted to engage a pair of 00- operating rails 14 and 15 at the sides of the hatchway. As shown, the side rails 14 and 15 are channel shape in cross section, the side portions 16 and 17 serving as guides for the-guide shoes 10,11, 12 and 13 and the other side portions 18 and 19 serving as braking surfaces to be engaged by a safety device 20.

The safety device 20is mounted on the bottom of the car for the purpose of stopping the car when it falls or starts to run away and comprises a frame 21 in the outer ends of which are pivotally disposedtwo pairs of gripping jaws 22 and 23 for engaging the braking surface 18 and 19 on the side rails 14 and 15 and bringing the car to a stop when it starts to fall or run away.

The means for operatin the gripping jaws 22 and 23 comprises a safety rope 24 that passes over a sheave 2501's the frame 21. The outer endof the safety rope 24 is disposed to be secured to the usual governor cable, in a manner well known in the elevator art, as illustrated and described in the coending application of James Dunlop, Ser1al No. 337,950, filed February 6, 1929 and assigned to the Westinghouse Electric & Mfg. Q0. The inner end of the safety rope 24 is wound around a spiral groove on the outer surface of, and is secured to, a safety drum 26 that is mounted between a pair of cross members 27 and 28 in the central part of the frame 21.

The safety drum 26 is disposed upon, and keyed to, a shaft 29 that is rotatably mounted in the cross members 27 and 23. The shaft '29 is provided with a right and a left-hand screw-threaded central. aperture 30 for receiving the inner ends of a pair of cooperating right and left-hand screw-threaded shafts 31 and 32 that are slidably disposed in apair of cross members 33 and 34 on the frame 21.

Upon the outer ends of the shafts 31 and 32 are mounted cam members 35 and 36 that are respectively disposed between the rear arms 37, 38, 39 and 40 of-the gripping aws 22 and 23. A plurality of rollers 41 are mounted in the central portions of the ends of the arms 37, 38, 39, and 40 for engaging the cam members 35 and 36 to reduce the friction therebetween when the cams are moved inwardly by the shafts 31 and 32 to close the clamping jaws.

The apparatus thus far described is employed for stopping the car when it starts to fallor run away downwardly.

In order to stop the elevator car efl'ective'ly and hold it rigidly at a landing, regardless of any variations in its lead, while it is being loaded and unloaded, it is desirable to have a brake mounted directly upon the car itself rather than to depend solely upon applying a braking effect to the motor shaft of the hoisting apparatus. Therefore, I have provided additional operating apparatus for the gripping jaws 22 23 so-that they may be utilized for applying a braking effect to the car each time a stop is made, as

well as for the purpose of stopping the car when it falls or runs away.

In order to employ the gripping jaws 22 and 23 as brakes, the engaging surface of each jaw is enlarged and is provided with a pair of brake shoes 43. The brake shoes 43 are pivotally mounted in the braking jaws in such manner that they may be removed andreplaced readily when worn or otherwise damaged.

The additional means for operating the gripping jaws .22 and 23 as braking devices comprises a plurality of members45, 46, 47

and 48 of cam-shape that are disposed between a plurality of rollers 49, 50, 51 and 52 which are mounted upon the inner ends of the arms 37, 38, 39 and 40. of the gripping jaws 22 and 23. The cam members 45, 46, 47 and 48 are mounted upon the outer ends of a plurality of shafts 53,-54, 55 and 56 that are slidably disposed beside the shafts 31 and 32 in the cross members 33 and 34 insuch manner that they will, when moved inwardly, pull the cam members 45, 46, 47 and 48 between the pairs of rollers49, 50, 51 and 52 and into engagement with the braking surfaces of the side rails 14 and 15.

In order that the sliding shafts 53, 54, 55 and 56 may be biased inwardly toset the gripping jaws against the guide rails, each shaft is provided with a spring 57 that is compressed between a nut 58 on the inner end of the shaft and the cross piece in which the shaft is slidably mounted.

For the purpose of overcoming the biasing effect of the springs 57 on the sliding shafts 53 and 54 when it is desired to release the gripping jaws 22, a lever 60 is pivotally mounted in a pair of brackets 61 and 62 uponthe frame 21 in such manner that a pair of shoulders 63 thereon will bear against the inner ends of the shafts 53 and 54. When'the lever 60 is moved outwardly by a piston 64 that is disposed in a fiuid pressure cylinder 65, itwill cause the springs on the shafts 53 V and 54 to be compressed and thereby release the gripping jaws 22. V I

Similarly, a lever 66 is pivotally mounted in a pair of brackets 67 and 68 on the frame 21 in such position that it may bear against the inner ends of the shafts 55 and 56 when operated by a piston 69 in the right-hand end of the fluid-pressure cylinder 65 and thereby cause the gripping jaws 23 to be released.

As shown in Fig. 5, the levers 60 and. 66 are shaped like inverted Ys so that they may straddle the shafts 31 and 32 and yet be easily operated by the pistons 64 and 69.

The means for supplying the fluid pressure to the fluid-pressure cylinder 65 to move the pistons 64 and 69 outwardly comprises a pressure tank 70 and a storage tank 71 that are connected to the cylinder 65 by means of pipes 72, 7 3 and 74. A motor-operated pump 42 is mounted between the pressure tank 7 O andthe storage tank 71to maintaina suitable pressure in the pressure tank. 7

The means for .controlling the application of fluid pressure tothe fluid-pressure-cylinder comprises a valve 75 that is employed to connect the pipes 72, 7 3 and 74 in such manner that the cylinder 65 may be connected to either the pressure tank or the storage tank, as desired.

The valve 75 may be controlled by any suitable means, such as an electromagnet 76, the coil of which is connected in the circuit for controlling the operation of the hoisting :5 to move downwardly and thereby shut off the pressure tank and connect the cylinder 65 to the storage tank 71. With this arrangement of the apparatus, the braking jaws 22 and 23 will be applied to the side rails when the power is cut off to make a stopand will be released therefrom when power is applied to start the car.

Inasmuch as the compression springs 57 may be selected to impart any desired pressure to the braking jaws, it is possible to provide for applying a predetermined braking pressure tothe car when each stop is made. It should also be noted that the side rails 14 and 15 are provided with flanges 16 and 17 for the guide shoes and with separate flanges 18 and 19 for the braking shoes. Therefore, the guide-shoe flanges may be readily lubricated to reduce the friction with the guide shoes while the brake-shoe flanges may be left dry and unlubricated to provide a good friction surface for the brake shoes. The invention may be understood best by an assumed operation thereof.

Assuming that the car C is standing at a floor and that the operator has moved the car switch Cs in a clockwise-direction, then the up-direction switch 1 will. be energized to'start the car by way of a circuit that extends from'supply conductor L1, through conductor 80, the contact members 81,82 and 83 of car switch Cs, conductor 84, the coil of up-direction switch 1 and conductor 85, to supply conductor L2.

The closing of the contact members 0; and b .on the up-directon switch 1 energizes the field winding GF of the generator with current in one direction by way of a circuit that extends from supply conductor L1, through conductors 86' and 87, the contact 5 members Z) of up-direction switch 1, conductors 88 and 89, the field winding GF, conductors 90and 91, the'contact members a of up-direc'tion switch 1, conductor 92, resistor, sections R andR and conductor 93,

ytosupply conductor L2. The .energization thereby effect the release of the braking jaws fromthe brake surfaces of the side rails 14 and 15, which circuit extends fromsupply conductor L1, through conductor 80, the coil of the electromagnet 76, conductors 94 and 95, the contact members a of up direction switch land conductor 96, to supply conductor L2.

The energization of theelectromagnet 76 causes the valve to move upwardly, thus closing the opening between the fluid-pressure cylinder 65 and the storage tank 71 and, at the same time, opening the connection between the pressure tank 70 and the fluidpressure cylinder 65. As fluid pressure passes from the pressure tank 7 0 to the cylinder 65, the pistons 64 and69 are driven outwardly against the upper ends of the levers 60 and 66. The outward movement of the levers 60 and 66 presses them against the inner ends of the sliding shafts 53, 54, 55 and 56 on which the cam members 45,46, 47 and 48 are mounted and moves them outwardly. The removal of the cam members 45, 46, 47 and 48 from between the rollers 49, 50, 51 and 52 on the inner ends of the arms 37, 38, 39 and 40 of the braking aws 22 and 23 permits the arms to close and thereby release the braking jaws from the braking surfaces 18 and 19, thus freeing the car so that it may move.

As the car attendant continues the movement of the car switch C8 in a clockwise clirection, a circuit is completed for operating the car at an intermediate speed, which circuit extends from supply conductor L1, through conductor 80, the contact members 81, 82 and 99 of the car switch Cs, conductor 100, the coil of intermediate speed relay LR and conductor 101, to supply conductor L2.

The closing of the contact members on the intermediate-speed relay LR completes a circuit to shunt the resistor section B from the circuit previously traced for the field' winding GrF to thereby cause the car to travel at a higher speed. 7

If it is desired to cause the car to travel at a still greater speed, the car switch Gs may be moved in a'clockwise direction to a further position for completing a circuit for energizing'the high-speed relay HR, which circuit extends from supply conductor L1, through conductor the contact members 81, 82 and 102 of car switch Gs, conductor 103, the coil of high-speed relay HR and conductor 101, to supply conductor L2.

The energization of the high-speed relay HR and the closing of its contact members serves to shunt the resistor section B from the circuit previously traced for the field winding GF, thereby allowing full line volta e to be su lied to the windin GF to cause a PP b the car to travel at high speed.

Assuming now that the attendant on the car desires to stop the car at a landing and, therefore, moves the car switch Ca in a counterclockwise direction, to its central position, then the circuits for the coils of the high-speed relay HR, the intermediate-speed relay LR and the up-direction switch 1 will be opened successively to slow down the generator G and disconnect it from its source of power to bring the elevator car C to a stop.

The opening of the contact members 0 on the deenergized up-direction switch] opens the circuit for the electromagnet 76 and permits the valve 75 to move downward ly to cause the gripping jaws 22 and 23 to be applied to the side rails 14: and 15 to effect a braking action on the car for causing it to come to a stop and be held rigidly at the desired landing.

The downward movement of the valve 75 closes the pipe between the pressure tank 70 and the fluid pressure cylinder and, at the same time, opens the pipe from the pressure cylinder 65 to the storage reservoir 71, thus releasing the pressure on the pistons 64' and 69 to permit them to move inwardly. As the pistons 6 and 69 move inwardly, they re lease the upper ends of the levers 60 and 66, thereby permitting the compression springs 57 to push the sliding shafts 53, 54:, 55, and 56 inwardly and draw the cam members45, 46, 4:7 and t8'between the pairs ofrollers 49, 50, 51 and 52. I V i The movement of the cam members 45, 46, 17 and 48 between the rollers 49, 50, 51 and 52 spreads the inner ends of the arms 37, 38, 39 and 40 on the gripping jaws 22 and 23 and thereby applies the brake shoes 43 to the braking surfaces 18 and 19 0f the side rails 14 and 15, thus bringing the car to a'stop and holding it rigidly at the landing while it is being unloaded and loaded.

If the car starts to fall or run away downwardly during its normal operation, the safety device 20 will operate the gripping jaws 22 and 23 to bring the car to a stop in the usual manner. Inasmuch as the operationof such safety devices is old and well known in the art, a detailed description thereof will not operatively connecting the motor to, and.

operatively disconnecting it from, a source of power, a plurality of braking jaws disposed on thecar for gripping the rails and means for operating the braking jaws to stop the car when it starts to fall or run away, of additional independent actuating means operably responsive to operation of the controlling means for actuating the braking jaws to apply a mild braking effect to the car while the motor is operatively disconnected from its source of power.

The combination with a car operable between a pair of rails in a hatchway, a motor for operating the car, controlling means for operatively connecting the motor to, and

operatively disconnecting it from, a source of power, a plurality of braking jaws disposed on the car for gripping the rails, and means for operating the braking jaws to stop the car when it starts to fall or run away, of addi tional ndependent actuating means operably responsive to operation of the controlling means for actuating the braking jaws to apply a predetermined braking efi'ect to the car while the motor is operatively disconnected from its source of power.

3. The combination with a car operable'between a pair of rails in a hatchway, a motor for operating the car, controlling means for operatively connecting the motor to, and operatively disconnecting it from, a source of power, a plurality of braking jaws disposed on the car, and means for operating the braking jaws to grip the rails and stop the car when it starts to tailor run away, of additional means for operating said braking aws to apply a braking effect to the car while the motor is operatively disconnected from its source of power, said additional means comprising a spring and independent wedge actuators for applying pressure to the braking jaws, fluid-pressure means for controlling the spring and means operably responsive to movement of the controlling means for controlling the fluid-pressure means to effect the application of-the spring to the brakingjaws.

4. In an elevator system, an elevator car, a hatchway in which said car operates, guide means on said car, a safety brake on said car and a guide rail in said hatchway of channel configuration in cross section, one leg of which cooperates with said guide means and the other leg of which cooperates withsaid safety brake.

5. In combination, an elevator car operable between guide rails, a safety device comprising rail gripping jaws, wedge actuators associated therewith, means responsive to emergency conditions for forcing said wedge actuators between the adjacent jaws whereby the jaws are moved to rail gripping position,

auxiliary wedge actuators, springs tending to move said auxiliary wedge actuators to engage said jaws, and means controllable by the operator for rendering said springs inefiective.

6. A safety device comprising rail gripping jaws, wedge actuators associated therewith, a cable drum with threaded portions for engaging the wedge actuators to move them to rail gripping position when a cable is unreeled from the drum, auxiliary wedge actuators, springs biasing said auxiliary wedge actuators to engage the jaws, and means opposing the springs to render them ineffective.

In testimony whereof, I have hereunto subscribed my name this 23rd day of May, 1929.

HENRY D. JAMES. 

